May 20, 2015
Let's talk about resection of an Optic Glioma via the Pterional Craniotomy. This is a 10 year-old boy with visual dysfunction, was evaluated in the emergency room and was noted to have a relatively cystic heterogeneously enhancing mass centered around the area of the optic chiasm. There's also extension of the cyst into the left subfrontal area. This patient subsequently underwent a left pterional craniotomy. You can see this subfrontal approach. Dynamic retraction was used to elevate the frontal lobe. The lobe appeared very tense at the beginning, however, ample amount of CSF was drained through the optical carotid cisterns. Now you can see the mass engulfing the ipsilateral optic nerve. The arachnoid bands of the subfrontal area were dissected, so that the frontal lobe can be further elevated. Also the anterior limb of the Sylvian fissure was split. You can see the tumor extending between the carotid artery and the optic nerve. I continue to dissect the tumor and open its capsule. My operative strategy involve the removing as much of the tumor as possible, while leaving both optic nerves intact. The cyst within the frontal lobe was also entered and removed. Here you can see the suprachiasmatic cistern over the arachnoid bands or dissected. Here's the contralateral optic nerve, it's inspection reveals that it's minimally affected by the tumor. Tumor primarily involves the left optic nerve and part of the chiasm. Frontal lobe again is disconnected, so it can be mobilized. Now I work between ipsilateral optic nerve and carotid artery to remove as much of the tumor as possible. Ring curettes are used for evacuation of the tumor. Here's this portion of the tumor, continuing into the interpeduncular cisterns. Here's portion of the tumor above the chiasm into the frontal lobe. You can see the majority chiasm on the left side is infiltrated by the tumor. This part of the tumor appeared very fibrous and potentially, partially calcified. In the interior edge of the chiasm, can see how the optic nerve is very much infiltrated by the tumor on the left side. But since some functional vision was present, this nerve was protected. So I continue to work within the optical carotid triangle, removing the tumor underneath the chiasm. Again moving from one compartment of the tumor to another one, to remove the tumor. Here's the posterior capsule of the tumor facing the Interpeduncular cisterns. Basilar arteries at the depth of our dissection. Here's the A1 entering part of the tumor mass. I just worked around the optic nerve ipsilaterally remove as much of the discolored tumor, without placing the nerve at risk. And you can see the nerve is being isolated from the component of the tumor, infiltrating the posterior fossa. Pituitary rongeurs are used to further evacuate the tumor. Most of the dissection is occurring between the optic nerve and carotid artery, where most of the tumor is centered at. So this is primarily a subchiasmatic tumor. Now that the tumor is heavily debulked, the cyst of the tumor is mobilized away from the contents of interpeduncular cisterns. This capsule is gently mobilized. Here's a look into the posterior fossa. The tumor is gently mobilized into our resection cavity, out of the operative blind spots. Additional use of angled instruments to inspect the operative blind spots located more posteriorly. The third nerve on the right side should be right across from our resection cavity, based on this operative trajectory. Basilar artery and the P1 branches are apparent. Here again ipsilateral optic nerve, carotid artery ,the bifurcation, removing the tumor piecemeal between different operate windows. Preparing soaked gelfoam pledges were used to bathe the arteries and relieve their vasospasm. Here's a final view of the operative cavity, the optic nerve, obviously infiltrated by the tumor carotid artery, different operative windows used for resection of the mass. Portion of the tumor that was easily dissectable from the chiasm was also removed. And in this case, postoperative MRI revealed an excellent extent of resection considering the location and the infiltration capacity of the tumor into the optic nerve, patient made an excellent recovery and his vision remains stable. Thank you.
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